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icon-touxiang" data-v-06225672><a href="https://github.com/linxin1123" target="_blank" title="作者" class="beLink" data-v-06225672>lingxin</a></div> <div title="创建时间" class="date iconfont icon-riqi" data-v-06225672><a href="javascript:;" data-v-06225672>2023-01-25</a></div> <!----></div></div></div> <!----> <div class="content-wrapper"><div class="right-menu-wrapper"><div class="right-menu-margin"><div class="right-menu-title">目录</div> <div class="right-menu-content"></div></div></div> <h1><img src="">HTML与CSS学习第3天<!----></h1>  <div class="theme-vdoing-content content__default"><h1 id="html-与-css-学习第-3-天"><a href="#html-与-css-学习第-3-天" class="header-anchor">#</a> HTML 与 CSS 学习第 3 天</h1> <p><img src="https://img-blog.csdnimg.cn/5f6b9203022f4cbb9a7734c98cbaaca6.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBA5YeM5q2G,size_20,color_FFFFFF,t_70,g_se,x_16#pic_center" alt="在这里插入图片描述"></p> <p>@<a href="%E7%9B%AE%E5%BD%95">TOC</a></p> <h2 id="_1-css"><a href="#_1-css" class="header-anchor">#</a> 1.CSS</h2> <h3 id="_1-1-css-介绍"><a href="#_1-1-css-介绍" class="header-anchor">#</a> 1.1 css 介绍</h3> <ul><li><strong>css：层叠样式表</strong></li> <li>作用：给 HTML 页面设置样式</li></ul> <h3 id="_1-2-css-语法"><a href="#_1-2-css-语法" class="header-anchor">#</a> 1.2 css 语法</h3> <ul><li><p><strong>写法：写在 style 标签中，style 标签写在 head 标签里，title 标签下</strong></p></li> <li><p>语法：选择器{</p> <p>​ 属性键值对；</p> <p>}</p></li> <li><p><strong>示例</strong></p></li></ul> <div class="language-html line-numbers-mode"><pre class="language-html"><code><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>style</span><span class="token punctuation">&gt;</span></span><span class="token style"><span class="token language-css">
  <span class="token comment">/* h1标签这里为选择器 */</span>
  <span class="token selector">h1</span> <span class="token punctuation">{</span>
    <span class="token comment">/* color为文字颜色属性 */</span>
    <span class="token property">color</span><span class="token punctuation">:</span> dodgerblue<span class="token punctuation">;</span>
    <span class="token comment">/* font-size为字体大小 */</span>
    <span class="token property">font-size</span><span class="token punctuation">:</span> 40px<span class="token punctuation">;</span>
    <span class="token comment">/* background-color为标签范围背景颜色 */</span>
    <span class="token property">background-color</span><span class="token punctuation">:</span> blueviolet<span class="token punctuation">;</span>
    <span class="token comment">/* width，height为标签范围s宽度和高度 */</span>
    <span class="token property">width</span><span class="token punctuation">:</span> 1000px<span class="token punctuation">;</span>
    <span class="token property">height</span><span class="token punctuation">:</span> 400px<span class="token punctuation">;</span>
  <span class="token punctuation">}</span>
</span></span><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>style</span><span class="token punctuation">&gt;</span></span>
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br></div></div><ul><li>常见属性</li></ul> <table><thead><tr><th>属性名</th> <th>作用</th></tr></thead> <tbody><tr><td>color</td> <td>文字颜色</td></tr> <tr><td>font-size</td> <td>文字大小</td></tr> <tr><td>background-color</td> <td>背景颜色</td></tr> <tr><td>width</td> <td>宽度</td></tr> <tr><td>height</td> <td>高度</td></tr></tbody></table> <ul><li><strong>注意点：每一个样式键值对写完后以分号结尾。</strong></li></ul> <h3 id="_1-3-css-引入方式"><a href="#_1-3-css-引入方式" class="header-anchor">#</a> 1.3 css 引入方式</h3> <table><thead><tr><th>引入方式</th> <th>书写位置</th> <th>作用范围</th> <th>使用场景</th></tr></thead> <tbody><tr><td>内嵌式</td> <td>写在 style 标签中，前文提到的方式</td> <td>当前页面</td> <td>小案例</td></tr> <tr><td>外联式</td> <td>写在单独的 css 文件中，通过 link 标签引入</td> <td>多个页面</td> <td>项目中</td></tr> <tr><td>行内式</td> <td>css 写在标签的 style 属性中</td> <td>当前标签</td> <td>配合 js 使用</td></tr></tbody></table> <ul><li><strong>内嵌式示例</strong>：</li></ul> <div class="language-html line-numbers-mode"><pre class="language-html"><code><span class="token comment">&lt;!-- 内嵌式 --&gt;</span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>style</span><span class="token punctuation">&gt;</span></span><span class="token style"><span class="token language-css">
  <span class="token selector">p</span> <span class="token punctuation">{</span>
    <span class="token property">color</span><span class="token punctuation">:</span> red<span class="token punctuation">;</span>
  <span class="token punctuation">}</span>
</span></span><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>style</span><span class="token punctuation">&gt;</span></span>
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br></div></div><ul><li><strong>外联式示例</strong>：</li></ul> <div class="language-html line-numbers-mode"><pre class="language-html"><code><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>link</span> <span class="token attr-name">rel</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">&quot;</span>stylesheet<span class="token punctuation">&quot;</span></span> <span class="token attr-name">href</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">&quot;</span>02.css<span class="token punctuation">&quot;</span></span> <span class="token punctuation">/&gt;</span></span>
rel属性代表地址文件为样式表
<span class="token comment">&lt;!--书写的位置与内嵌式相同 --&gt;</span>
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br></div></div><ul><li><strong>行内式示例</strong>：</li></ul> <div class="language-html line-numbers-mode"><pre class="language-html"><code><span class="token comment">&lt;!-- 行内式 --&gt;</span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>p</span> <span class="token special-attr"><span class="token attr-name">style</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">&quot;</span><span class="token value css language-css"><span class="token property">color</span><span class="token punctuation">:</span> red<span class="token punctuation">;</span></span><span class="token punctuation">&quot;</span></span></span><span class="token punctuation">&gt;</span></span>我是大傻逼<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>p</span><span class="token punctuation">&gt;</span></span>
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br></div></div><h2 id="_2-选择器"><a href="#_2-选择器" class="header-anchor">#</a> 2. 选择器</h2> <h3 id="_2-1-选择器作用"><a href="#_2-1-选择器作用" class="header-anchor">#</a> 2.1 选择器作用</h3> <p>选中页面对于的标签，方便后续设置样式</p> <h3 id="_2-2-常见的选择器"><a href="#_2-2-常见的选择器" class="header-anchor">#</a> 2.2 常见的选择器</h3> <table><thead><tr><th>选择器名</th> <th>语法规则</th> <th>作用</th></tr></thead> <tbody><tr><td>标签选择器</td> <td>标签名{css 属性名:属性值;}</td> <td>通过标签名，找到页面中<strong>所有这类标签</strong>，设置样式</td></tr> <tr><td>类选择器</td> <td><strong>.类名</strong>{css 属性名:属性值;}</td> <td>通过类名，找到页面中<strong>所有带有这个类名的标签</strong>，设置样式</td></tr> <tr><td>id 选择器</td> <td><strong>#id 属性值</strong>{css 属性名:属性值;}</td> <td>通过 id 属性值，找到页面中所有带有这个 id 属性值的标签，设置样式</td></tr> <tr><td>通配符选择器</td> <td>*{css 属性名:属性值;}</td> <td>找到页面中的<strong>所有标签</strong>，设置样式</td></tr></tbody></table> <h4 id="注意点"><a href="#注意点" class="header-anchor">#</a> <strong>注意点</strong></h4> <ul><li>类名以数字，字母，下划线，中划线组成，但不能以数字或中划线开头</li> <li><strong>一个标签可有多个类名，类名之间以空格隔开</strong></li> <li><strong>类名可以重复（即多个标签可以有相同类名）</strong></li> <li><strong>id 属性值在一个页面中是唯一的</strong></li> <li><strong>1 个标签上只可以有一个 id 属性值</strong></li> <li><strong>1 个 id 选择器只能选中一个标签</strong></li> <li>除非有特殊情况，否则不要使用 id 设置样式</li></ul> <h3 id="_2-3-选择器示例"><a href="#_2-3-选择器示例" class="header-anchor">#</a> 2.3 选择器示例</h3> <ul><li>标签选择器</li></ul> <div class="language-html line-numbers-mode"><pre class="language-html"><code>div { font-family: 'Courier New', Courier, monospace; }
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><ul><li>类选择器</li></ul> <div class="language-html line-numbers-mode"><pre class="language-html"><code>.a3 { color: blueviolet; }
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><ul><li>id 选择器</li></ul> <div class="language-html line-numbers-mode"><pre class="language-html"><code>#a1 { color: brown; } #a2 { color: blue; }
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><ul><li>通配符选择器</li></ul> <div class="language-html line-numbers-mode"><pre class="language-html"><code><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>style</span><span class="token punctuation">&gt;</span></span><span class="token style"><span class="token language-css">
  <span class="token selector">*</span> <span class="token punctuation">{</span>
    <span class="token property">color</span><span class="token punctuation">:</span> #101010<span class="token punctuation">;</span>
  <span class="token punctuation">}</span>
</span></span><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>style</span><span class="token punctuation">&gt;</span></span>
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br></div></div><h2 id="_3-字体和文本样式"><a href="#_3-字体和文本样式" class="header-anchor">#</a> 3. 字体和文本样式</h2> <h3 id="_3-1-字体相关属性"><a href="#_3-1-字体相关属性" class="header-anchor">#</a> 3.1 字体相关属性</h3> <table><thead><tr><th>属性名</th> <th>属性值</th> <th>描述</th></tr></thead> <tbody><tr><td>font-size</td> <td>数字+px</td> <td>字体大小，<strong>谷歌默认字体大小为 16px</strong></td></tr> <tr><td>font-weight</td> <td>normal 或 400 或者 bold 或 700，<strong>还可取 100-900 的值，但字体不一定有 9 种粗细。</strong></td> <td>400 和 normal 为正常，700 或 bold 为加粗</td></tr> <tr><td>font-style</td> <td>normal 或 italic</td> <td>normal 为正常，italic 为倾斜</td></tr> <tr><td>font-family</td> <td>具体字体名 1,具体字体名 2,.....字体系列</td> <td>从左往右找字体，已经安装就应用该字体</td></tr> <tr><td>font</td> <td>style weight size family</td> <td>字体属性值连写，swsf，代表上述四个属性</td></tr></tbody></table> <h3 id="_3-2-字体的一些注意点"><a href="#_3-2-字体的一些注意点" class="header-anchor">#</a> 3.2 字体的一些注意点</h3> <ul><li><p>字体系列</p> <table><thead><tr><th>字体系列</th> <th>特点</th></tr></thead> <tbody><tr><td>无衬线字体</td> <td>横平竖直</td></tr> <tr><td>衬线字体</td> <td>横细竖粗，首尾有笔锋</td></tr> <tr><td>等宽字体</td> <td>每个字母或文字宽度相同</td></tr></tbody></table></li> <li><p>默认字体</p> <table><thead><tr><th>系统</th> <th>字体</th></tr></thead> <tbody><tr><td>windows</td> <td>微软雅黑</td></tr> <tr><td>mac os</td> <td>苹方</td></tr></tbody></table></li> <li><p>font 属性连写</p> <ul><li><strong>只能省略前两个属性</strong></li> <li><strong>省略了相当于设置了默认值</strong></li></ul></li></ul> <h3 id="_3-3-文本样式"><a href="#_3-3-文本样式" class="header-anchor">#</a> 3.3 文本样式</h3> <table><thead><tr><th>样式</th> <th>属性名</th> <th>属性值</th></tr></thead> <tbody><tr><td>文本缩进</td> <td>text-indent</td> <td>数字+px 或数字+<strong>em（em 为当前标签的 font-size 大小）</strong></td></tr> <tr><td>文本水平对齐方式</td> <td><strong>text-align</strong></td> <td>left（左对齐）/center（居中对齐）/right（右对齐）</td></tr> <tr><td>文本修饰</td> <td>text-decoration</td> <td>underline（下划线）/none（无装饰）</td></tr></tbody></table> <h3 id="_3-4-文本样式注意点"><a href="#_3-4-文本样式注意点" class="header-anchor">#</a> 3.4 文本样式注意点</h3> <ul><li><p><strong>text-align:center 能让哪些元素水平居中</strong></p> <ul><li>文本</li> <li>span 标签，a 标签</li> <li>input 标签，img 标签</li></ul></li> <li><p><strong>如果要让以上元素水平居中，text-align:center 需要给以上元素的父元素设置</strong>。</p></li></ul> <h3 id="_3-5-水平居中方法总结"><a href="#_3-5-水平居中方法总结" class="header-anchor">#</a> 3.5 水平居中方法总结</h3> <ul><li>实现 div，p，h（大盒子）水平居中
<ul><li>通过设置样式 margin:0 auto;实现</li></ul></li> <li>注意点
<ul><li><strong>直接给当前元素设置即可</strong></li> <li><strong>margin:0 auto;一般针对于固定宽度的盒子，如果合子没有设置宽度，此时会默认占满父元素的宽度</strong></li></ul></li></ul> <h3 id="_3-6-行高"><a href="#_3-6-行高" class="header-anchor">#</a> 3.6 行高</h3> <ul><li>作用：控制一行的上下行间距</li> <li>属性名：line-height</li> <li>取值：1.数字+px，<strong>2.倍数（当前标签 font-size 的倍数）</strong></li> <li><strong>让单行文本垂直居中对齐</strong> <ul><li><strong>设置 line-height:文字父元素高度</strong></li></ul></li> <li><strong>取消上下间距</strong> <ul><li><strong>line-height：1</strong></li></ul></li> <li><blockquote><p><strong>行内元素不可以设置宽高，宽度高度随文本内容的变化而变化，但是可以设置行高（line-height），同时在设置外边距 margin 上下无效，左右有效，内填充 padding 上下无效，左右有效；块级元素可以设置宽高，并且宽度高度以及外边距，内填充都可随意控制。</strong></p></blockquote></li></ul> <h2 id="_4-chorm-调试工具"><a href="#_4-chorm-调试工具" class="header-anchor">#</a> 4. chorm 调试工具</h2> <ul><li>图解</li></ul> <p><img src="https://img-blog.csdnimg.cn/47bdae10010b459aa1459213df221c94.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBAcXFfMzM5MzgyMzQ=,size_20,color_FFFFFF,t_70,g_se,x_16#pic_center" alt="调试工具的使用"></p> <h2 id="_5-颜色常见取值"><a href="#_5-颜色常见取值" class="header-anchor">#</a> 5. 颜色常见取值</h2> <table><thead><tr><th>颜色表示方式</th> <th>表示含义</th> <th>属性值</th></tr></thead> <tbody><tr><td>关键词</td> <td>预定义的颜色名</td> <td>red，green，blue</td></tr> <tr><td>rgb 表示法</td> <td>红绿蓝三原色，每项取值范围 0-255</td> <td>rgb(0,0,0),rgb(255,255,0),....</td></tr> <tr><td>rgba 表示法</td> <td>红绿蓝三原色加上透明度 a，a 取值范围 0-1</td> <td>rgba(255,255,255,0.5),rgba(255,255,0,0.3)</td></tr> <tr><td>十六进制表示法</td> <td>#开头，将数字转换成十六进制表示</td> <td>#000000、#ff0000、#e92322，缩写：#000，#f00</td></tr></tbody></table></div></div>  <div class="page-edit"><div class="edit-link"><a href="https://github.com/linxin1123/vuepress-blog/edit/master/docs/01.前端/41.HTML笔记/03.HTML与CSS学习第3天.md" target="_blank" rel="noopener noreferrer">编辑</a> <span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></div> <!----> <div class="last-updated"><span class="prefix">上次更新:</span> <span class="time">2023/02/17, 11:29:32</span></div></div> <div class="page-nav-wapper"><div class="page-nav-centre-wrap"><a href="/pages/fa03a8/" class="page-nav-centre page-nav-centre-prev"><div class="tooltip">HTML与CSS学习第2天</div></a> <a href="/pages/024faa/" class="page-nav-centre page-nav-centre-next"><div class="tooltip">HTML与CSS学习第4天</div></a></div> <div class="page-nav"><p class="inner"><span class="prev">
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